Check codes for your area, but gas lines must be 14 or 16 inches minimum depth. Deep is defined as from ground to the top of the pipe. That means trench depth of 18 inches or more.
Careful as you go past trees, some people will dig under the roots to avoid damage to the tree and reduce possibility of strong wind toppling them.
The piping from the street up to, and including the meter, is the GAS company’s hardware. You can trench it, but leave the material installation to them. FYI, street gas pressure is around 40 psi.
You can install your own piping. It’s easier to install house piping after the meter is already there, but there are advantages to pre-piping.
When I do my own piping, I calculate the BTU totals and figure the pipe size presuming 11 inches of water. In your case, I’d use AT LEAST 1-inch black iron. (Me, I went with 1-1/4”). The double regulator method (40# to 2# to final) is risky. I also setup a test where I pressurized the pipes with 50 psi from regulated compressor using AIR, and check the joints. Presuming the meter regulator fails OPEN and you’re getting full street pressure.
Regarding house piping, I hate to say it, but black iron is the safest material. I hesitate because natural gas inherently contains hydrogen sulfide. Yeah, the gas providers are supposed to scrub and process the NG to minimize it, but I KNOW some gas sellers didn’t scrub at all.
Problem with hydrogen sulfide is when it combines with water vapors, it combines, breaks down and forms a mile aqueous solution of sulfuric acid which is VERY corrosive. Painting the inside of the pipes helps (YES, I do that by pulling saturated cotton through on a string). Some will use galvanized pipes, but that creates the white zinc oxide powder that can clog appliance valves if you’re not careful with debris traps. So some experts don’t recommend galvanized.
Finally, sealing pipe threads is many times, misunderstood. Some will use Teflon tape thinking it’s a sealant. It’s NOT. Teflon is a dry LUBRICANT. It doesn’t seal anything. The philosophy of tapered pipe threads is that metal will smash against each other (male-female) and form a true metal to metal seal. In the old days, that worked because pipes were LEAD, and the soft metal would comply in compressive yield. Black iron is actually mild steel and getting a true metal to metal seal involves highly precise machining and crazy high torque, and that’s ignoring high friction loads and galling. Remedy is to have a lubricating sealant. I’m an aerospace engineer by profession (mechanical by education) and some colleagues have petrochemical background. The petroleum processing plants see these threading problems on a more challenging scale. They use a graphite infused medium that will expand (2-3%). Graphite is a fantastic lubricant, much better than Teflon, and the expansion action seals in a more positive way than just brush-on goop. It’s hard to find because it’s an industrial product, not commercial.
So, use the goop if you can’t find anything better, but do NOT use it with Teflon tape. (We did serious testing in the lab, long story by Teflon is self-defeating). Make sure the threads are clean and dry (YES, I use an old toothbrush with soapy water on all the threads and blow dry). Torque until the pipes won’t turn anymore, for 1” pipe that may be 150-200 ft-Lbs force.
Good luck.
. Makes the customer have to run a service line and size the pipe accordingly. Depending on the pressure/distance it can be a real problem. 600’ a long ass run
